Process of stopping leakage of steam



Aug. 23, 1927. 1,640,062

' L. S. WATRES PROQESS OF STOPING LEAKAGE OF STEAM Filed June 1925 lNlfENTR.

I Armani-593'.

Patented Aug. 23, 1927.

UNITED STATES PATENT OFFICE.

LEWIS S. WATRES, OF SGRANTON, PENNSYLVANIA, ASSIGNOR TO NATIONAL GRAPH- ITE LUBRIGATION COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

PROCESS OF STOPPING LEAKAGE OI STEAM.

Applicationflled June 5, 1925. Serial No. 35,159.

This invention relates to a process for stopping leaks in the superheater of a steam boiler system. In steam boilers provided with superheaters, it has been found that the superheater is very liable to cause trouble, due to the development of leaks, because of thefact that this part of the apparatus is subjected to high temperatures, so that expansion and contraction due to changes in temperature subject the Joints especially to stresses and strains that are apt to cause leakage. The leaks are most apt to occur where units of the superheater are joined to the headers. It has been found that as soon as incipient leaks begln, the escape of the high temperature steam therethrough causes an abrading or cutting action, which soon enlarges the crack or hole to such an extent that it is necessary to shut down the boiler for repair. The seriousness of leaks in superheaters is often increased because the superheaters are frequently located in inaccessible positions, or are so placed that it is necessary to remove other apparatus before the superheaters can be reached for repairs.

By the present invention, inciplent leaks can be stopped before they have reached serious proportions, and the superheaters can be operated at very much longer intervals without requiring repair. In carrying out this invention, oil is introduced into the steam entering the superheater system and finds its way into the cracks or holes through which leakage of steam may be occurring, and then effectively prevents further leakage. The oil may be introduced into the steam either before it reaches the superheater or after it actually enters the superheater. It will, however, preferably be introduced into the saturated steam after this steam leaves the boiler proper and before it enters the superheater. The steam coming from the boiler is saturated and this seems to be the most suitable point for introducing the oil.

In the accompanying drawing in which a somewhat diagrammatic sketch of a locomotive boiler shown partly in section is illustrated, I indicate an arrangement by which the oil can be conveniently introduced into the superheater. In the drawing, reference character 1 indicates a locomotive boiler hav- .ing a dome 2 and a smoke stack 3. This boiler is provided with a steam pipe 4 lead ing to the manifold 5 for su rheater tubes the outlet pipe 7. It will be readily understood that by introducing oil into the oil cup 8 and opening the valve lO-to the proper extent, oil will be fed into the steam pipe 4 at the desired rate and will be carried by the steam into the superheater.

If there are any leaks in the superheater through which steam is escaping, some of the oil will be carried to the leakage places and stop the same.

The sort and amount of oil to be used for the purpose of stopping leaks will depend upon a variety of factors, such as the temperature to be reached in the superheater, the pressure of the steam that is to be used, the thickness of the walls of the tubes and header, the velocity of the steam through the tubes, etc.

I have found, for example, that ordinary lubricating oil for engine valves and cylinders is suitable for the usual locomotive boilers that are provided with superheaters and designed to be used with about 200 pounds of steam ,pressure. Heavier or thicker oils seem to be better for higher temperatures and pressures and where cracks have become somewhat larger or leaks have progressed somewhat farther.

In addition to the function of the oil in stopping'incipient leaks, as above described, and the advantages of its use for this purpose, the oil has also been foundto perform another useful function in the superheater. It has often been observed that after superheaters have been operated for some time, scales or incrustations form on the inside of the tubes and interfere with the efficient transmission of heat from the hot gases outside the tubes to the steam inside the tubes. These scales or incrustations arise from particles that are mechanically entrained with the steam and deposit on the inside of the tubes or from matter carried by the steam and deposited under the high temperature conditions. By introducing the oil into the steam, as above described, I have found that the inside of the tubes seem to be lubricated in such a manner that the tendency for the scales or incrustations to form therein is greatly lessened. The high velocity of the steam passing through the tubes appears to cause the oil to be carried along rapidly and polish the inside of the tubes, thus removing scale already formed therein and leaving the same with a bright metallic surface that greatly improves the thermal efficiency or transfer of heat. At the same time, the oil does not appear to form an incrustation in the bends or other portions of the-superheater to interfere with the proper operation of the same.

I claim:

1. The process of operating a steam boiler provided with a superheater, which comprises introducing oil into steam immediately before it enters the superheater.

2. The process of operating a steam boiler provided with a superheater, which comprises introducing oil into saturated steam immediately before it enters the superheater.

3. The process of operating a steam boiler provided with a superheater, which comprises introducing oil into steam after it leaves the boiler proper and before it enters the superheater.

at. The process of operating a steam boiler provided with a, superheater, which comprises introducing oil into steam which enters the superheater in sufficient amounts to cause residues from said oil to stop the leaks in said superheater.

5. The process of operating a steam boiler provided With a superheater, which comprises introducing oil into steam which enters the superheater in suflicient amounts to cause said oil to lubricate the inside surfaces of the superheater system to prevent scale from forming therein.

LEWIS S. WATRES. 

